JP6737150B2 - Wavelength conversion element, light source device, and projector - Google Patents

Description

The present invention relates to a wavelength conversion element, a light source device, and a projector.

Patent Document 1 discloses an excitation light source that emits excitation light, an optical system that collects the excitation light, a phosphor that emits fluorescence by being excited by the excitation light that has been collected, and a phosphor. There is disclosed a light source device including a glass substrate on which is formed. In this configuration, the phosphor is formed on one surface side of the glass substrate, and the cooling mechanism including the heat sink is provided on the one surface (excitation light incidence) side of the glass substrate, so that the phosphor can be efficiently cooled. .. Patent Document 1
In the above light source device, since the cooling fin is formed on the excitation light incident side (one surface side of the glass substrate) of the cooling mechanism, the translucent member cannot be provided on the excitation light incident side.

JP2012-169049A

When a translucent member having a high thermal conductivity or a translucent member having a good heat dissipation property (for example, sapphire) is provided on the excitation light incident side of the wavelength conversion layer, the light incident surface of the wavelength conversion layer is translucent. The adhesive used for joining the members has a refractive index of 1. to suppress interfacial reflection.
Between 76 (refractive index of translucent member) and 1.83 (refractive index of wavelength conversion layer), transparency and high heat resistance are required. However, there is no adhesive that satisfies such conditions.

The present invention has been made in view of the above-mentioned problems of the prior art, and it is possible to favorably provide a translucent member on the light incident surface side of the wavelength conversion layer, suppress interface reflection, and dissipate heat. It is an object of the present invention to provide a wavelength conversion element, a light source device, and a projector that can improve the wavelength conversion efficiency and suppress a decrease in wavelength conversion efficiency.

The wavelength conversion element in one aspect of the present invention includes a light incident surface on which excitation light is incident, a light emitting surface facing the light incident surface, an end portion of the light incident surface, and an end portion of the light emitting surface. A wavelength conversion layer having a connection surface for connection, a support member supporting the wavelength conversion layer and provided in contact with the connection surface, and a curved surface projecting in a direction opposite to the traveling direction of the excitation light. A cooling member having a translucent member that is provided so as to face the light incident surface of the wavelength conversion layer and that is joined to the support member via a joining member. An air layer is provided between the light incident surface and the translucent member, and the air layer is thinner than the thickness of the joining member.

According to the present invention, the air layer provided between the wavelength conversion layer and the light transmissive member can suppress the interfacial reflection while having the light transmissive property and enhance the heat dissipation of the wavelength conversion layer. it can.
Further, the air layer does not need to take heat resistance into consideration. This can prevent the wavelength conversion efficiency of the wavelength conversion layer from decreasing.

In the wavelength conversion element according to one aspect of the present invention, the support member has a non-bonding portion that is opposed to the transparent member and is not bonded to the transparent member, and the wavelength conversion layer is provided in the non-bonding portion. It may be arranged.

According to the present invention, the wavelength conversion layer is attached to the translucent member via the support member, and an air layer can be formed between the translucent member and the wavelength conversion layer.

In the wavelength conversion element according to one aspect of the present invention, the support member has a bonding surface that is bonded to the translucent member, and the light incident surface of the wavelength conversion layer is the excitation light rather than the bonding surface. By projecting in a direction opposite to the advancing direction, the stepped portion may be formed between the joining surface and the light incident surface.

According to the present invention, the light incident surface of the wavelength conversion layer can be brought closer to the translucent member. The thinner the air layer, the higher the heat transfer property, so that the heat of the wavelength conversion layer can be transmitted to the translucent member through the air layer and can be dissipated.

In the wavelength conversion element according to one aspect of the present invention, the translucent member may include sapphire, and the curved surface may have a hemispherical shape.

According to the present invention, by providing the translucent member made of sapphire having high thermal conductivity,
The heat generated in the wavelength conversion layer can be effectively dissipated in the translucent member.

In the wavelength conversion element according to one aspect of the present invention, the joint member may be provided with a vent hole that allows the air layer and the external space to communicate with each other.

According to the present invention, even when the air layer expands due to the heat generation of the wavelength conversion layer, the air can escape to the outside through the ventilation hole, and the separation between the translucent member and the support member, etc. Can be prevented.

A light source device according to one aspect of the present invention includes the wavelength conversion element described above and an excitation light source that emits the excitation light.

According to the present invention, since the wavelength conversion element having a high heat dissipation property while suppressing the interface reflection is provided, a light source device having a high wavelength conversion efficiency can be realized.

A projector according to an aspect of the present invention includes a light source device described above, a light modulation device that modulates light emitted from the light source device according to image information to generate image light, and projection optics that projects the image light. And a system.

According to the present invention, the projector is provided with the light source device having excellent wavelength conversion efficiency, and has high reliability.

1 is a schematic configuration diagram showing a projector of an embodiment. The figure which shows the schematic structure of the light source device in 1st Embodiment. Sectional drawing which cut|disconnected the wavelength conversion element in 1st Embodiment by the plane containing the illumination optical axis of FIG. The top view which looked at the wavelength conversion element in 1st Embodiment from the incident side of excitation light. Sectional drawing which follows the AA line of FIG. The figure which shows the structure of the light source device in 2nd Embodiment. Sectional drawing which cut|disconnected the wavelength conversion element in 2nd Embodiment by the plane containing the illumination optical axis of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Note that, in the drawings used in the following description, in order to make the features easy to understand, there may be a case where features are enlarged for convenience, and it is not always the case that the dimensional ratios of the respective components are the same as the actual ones. Absent.

[First Embodiment]
(projector)
The projector according to the present embodiment is an example of a projector that uses three transmissive liquid crystal light valves as a light modulator. A reflective liquid crystal ride valve may be used as the light modulator. Further, as the light modulation device, a light modulation device other than liquid crystal, such as a device using a micromirror, for example, a device using a DMD (Digital Micromirror Device) or the like, may be used.
FIG. 1 is a schematic configuration diagram showing the projector of the present embodiment.

As shown in FIG. 1, the projector 1 includes a light source device 2A, a color separation optical system 3, a light modulator 4R, a light modulator 4G, a light modulator 4B, a light combining optical system 5, and a projection optical system 6. , Are provided. The light source device 2A emits the illumination light WL. The color separation optical system 3 includes a light source device 2A.
The illumination light WL from is separated into red light LR, green light LG, and blue light LB. Light modulator 4R,
The light modulation device 4G and the light modulation device 4B respectively modulate the red light LR, the green light LG, and the blue light LB in accordance with image information to form image light of each color. The light synthesizing optical system 5 includes each light modulator 4R.
, 4G, and 4B, the image lights of the respective colors are combined. The projection optical system 6 projects the combined image light from the light combining optical system 5 toward the screen SCR.

As shown in FIG. 2, in the light source device 2A, of the blue excitation light B emitted from the semiconductor laser, part of the blue excitation light B emitted without wavelength conversion and the excitation by the wavelength conversion element 30. White illumination light (white light) that is a combination of yellow fluorescent light Y generated by wavelength conversion of light
Inject WL. The light source device 2A has illumination light W adjusted to have a substantially uniform illuminance distribution.
L is emitted toward the color separation optical system 3. The specific configuration of the light source device 2A will be described later.

As shown in FIG. 1, the color separation optical system 3 includes a first dichroic mirror 7a, a second dichroic mirror 7b, a first reflecting mirror 8a, a second reflecting mirror 8b, and a third reflecting mirror. The mirror 8c, the 1st relay lens 9a, and the 2nd relay lens 9b are provided.

The first dichroic mirror 7a separates the illumination light WL emitted from the light source device 2A into red light LR and light in which green light LG and blue light LB are mixed. Therefore, the first dichroic mirror 7a has a characteristic of transmitting the red light LR and reflecting the green light LG and the blue light LB. The second dichroic mirror 7b splits the mixed light of the green light LG and the blue light LB into the green light LG and the blue light LB. Therefore, the second dichroic mirror 7b has a characteristic of reflecting the green light LG and transmitting the blue light LB.

The first reflection mirror 8a is arranged in the optical path of the red light LR, and reflects the red light LR transmitted through the first dichroic mirror 7a toward the light modulation device 4R. Second reflection mirror 8b
The third reflection mirror 8c is arranged in the optical path of the blue light LB, and guides the blue light LB transmitted through the second dichroic mirror 7b to the light modulation device 4B.

The first relay lens 9a and the second relay lens 9b serve as the second relay lens 9b in the optical path of the blue light LB.
Is arranged in the subsequent stage of the dichroic mirror 7b. The first relay lens 9a and the second relay lens 9b compensate the optical loss of the blue light LB due to the optical path length of the blue light LB being longer than the optical path lengths of the red light LR and the green light LG.

Each of the light modulator 4R, the light modulator 4G, and the light modulator 4B is composed of a liquid crystal panel. Each of the light modulator 4R, the light modulator 4G, and the light modulator 4B transmits the red light LR, the green light LG, and the blue light LB while passing the red light LR and the green light L.
Each of the G light and the blue light LB is modulated according to the image information, and the image light corresponding to each color is formed. Polarizing plates (not shown) are respectively arranged on the light incident side and the light emitting side of each of the light modulator 4R, the light modulator 4G, and the light modulator 4B.

On the light incident side of each of the light modulator 4R, the light modulator 4G, and the light modulator 4B, the red light LR and the green light incident on the light modulator 4R, the light modulator 4G, and the light modulator 4B, respectively. A field lens 10R, a field lens 10G, and a field lens 10B for collimating LG and blue light LB are provided.

The light combining optical system 5 is composed of a cross dichroic prism. The light combining optical system 5 combines the image light of each color from each of the light modulator 4R, the light modulator 4G, and the light modulator 4B, and emits the combined image light toward the projection optical system 6.

The projection optical system 6 is composed of a projection lens group. The projection optical system 6 is a photosynthesis optical system 5
The image light combined by is enlarged and projected toward the screen SCR. As a result, an enlarged color image (image) is displayed on the screen SCR.

(Light source device)
Next, the configuration of the light source device 2A in the first embodiment will be described.
FIG. 2 is a diagram showing a schematic configuration of the light source device in the first embodiment.

As shown in FIG. 2, the light source device 2A includes an excitation light source 110, an afocal optical system 11, and
Homogenizer optical system 12, condensing optical system 20, wavelength conversion element 30, pickup optical system 60, first lens array 120, second lens array 130, and polarization conversion element 14.
0 and a superimposing lens 150.

The excitation light source 110 is composed of a plurality of semiconductor lasers 110A that emit blue excitation light B composed of laser light. The peak of the emission intensity of the excitation light B is 445 nm, for example. The plurality of semiconductor lasers 110A are arranged in an array in one plane orthogonal to the illumination optical axis 100ax. As the excitation light source 110, a semiconductor laser that emits blue light having a wavelength other than 445 nm, for example, 455 nm or 460 nm can be used. Further, the excitation light source 110 is not limited to the semiconductor laser diode, but may be an LED (Light
Emitting Diode) can also be used.

The afocal optical system 11 includes, for example, a convex lens 11a and a concave lens 11b. The afocal optical system 11 reduces the diameter of a light flux composed of a plurality of laser beams emitted from the excitation light source 110. A collimator optical system may be arranged between the afocal optical system 11 and the excitation light source 110 to convert the excitation light incident on the afocal optical system 11 into a parallel light flux.

The homogenizer optical system 12 includes, for example, a first multi-lens array 12a and a second multi-lens array 12b. The homogenizer optical system 12 makes the light intensity distribution of the excitation light uniform on the wavelength conversion layer described later, that is, a so-called top hat distribution. The homogenizer optical system 12 superimposes a plurality of small light beams emitted from the plurality of lenses of the first multi-lens array 12a and the second multi-lens array 12b, together with the condensing optical system 20, on the wavelength conversion layer. As a result, the light intensity distribution of the excitation light B with which the wavelength conversion layer is irradiated is made uniform.

The condensing optical system 20 includes, for example, a first lens 20a and a second lens 20b.
The condensing optical system 20 is arranged in the optical path from the homogenizer optical system 12 to the wavelength conversion element 30, and condenses the excitation light B into the wavelength conversion layer of the wavelength conversion element 30.
In the present embodiment, the first lens 20a and the second lens 20b are each composed of a convex lens.

The pickup optical system 60 includes, for example, a first collimating lens 62 and a second collimating lens 64. The pickup optical system 60 is a collimating optical system that substantially collimates the light emitted from the wavelength conversion element 30. The first collimating lens 62 and the second collimating lens 64 are each composed of a convex lens.

The first lens array 120 has a plurality of first lenses 122 for splitting the light emitted from the pickup optical system 60 into a plurality of partial light fluxes. The plurality of first lenses 122 are arranged in a matrix in a plane orthogonal to the illumination optical axis 100ax.

The second lens array 130 has a plurality of second lenses 132 corresponding to the plurality of first lenses 122 of the first lens array 120. The second lens array 130 forms an image of each first lens 122 of the first lens array 120 together with the superimposing lens 150 in the vicinity of the image forming area of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B. Let Multiple second lenses 1
32 are arranged in a matrix in a plane orthogonal to the illumination optical axis 100ax.

The polarization conversion element 140 converts the light emitted from the second lens array 130 into linearly polarized light. The polarization conversion element 140 includes, for example, a polarization separation film and a retardation plate (both not shown).

The superimposing lens 150 condenses each partial light beam emitted from the polarization conversion element 140 and superimposes the partial light beams in the vicinity of the image forming areas of the light modulators 4R, 4G, and 4B.

(Wavelength conversion element)
Next, the configuration of the wavelength conversion element according to the first embodiment will be described.
FIG. 3 is a cross-sectional view of the wavelength conversion element 30 in the first embodiment, taken along a plane including the illumination optical axis 100ax in FIG. FIG. 4 is a plan view of the wavelength conversion element according to the first embodiment viewed from the incident side of the excitation light B. FIG. 5 is a sectional view taken along the line AA of FIG.

As shown in FIGS. 3 and 4, the wavelength conversion element 30 includes a cooling unit 13 having a support member 31 and a translucent member 33, a reflective film 35, a wavelength conversion layer 32, and a dichroic film 34A.
And an antireflection film 34C.

The support member 31 is formed of a rectangular plate material and has a first surface (joint surface) 31a and a second surface 31b that face each other in the plate thickness direction. The pickup optical system 60 is provided on the second surface 31b side of the support member 31. The support member 31 includes a first surface 31a and a second surface 31a.
A hole (non-bonding portion) 31h penetrating in the thickness direction with respect to b is provided. First surface 31a
The shape of the hole 31h is rectangular when viewed from the normal line direction. The support member 31 may be made of a translucent material such as glass or quartz, or may be made of a non-translucent material such as a metal. In the case of a metal material, it is desirable to use a metal having excellent heat dissipation such as aluminum and copper.

The reflective film 35 is provided between the support member 31 and the wavelength conversion layer 32. That is, the reflective film 35 is provided on the inner peripheral surface 31e of the hole 31h of the support member 31. The reflective film 35 is
The fluorescent light (yellow light Y) generated by the wavelength conversion layer 32 is reflected. The reflective film 35 is preferably made of a metal material having a high light reflectance such as aluminum or silver.

The wavelength conversion layer 32 is provided and supported inside the hole 31h of the support member 31. When viewed from the direction normal to the light exit surface 32b of the wavelength conversion layer 32, the wavelength conversion layer 32 has a rectangular shape. The wavelength conversion layer 32 includes phosphor particles (not shown) that convert the blue excitation light B into yellow fluorescence light Y and emit the yellow fluorescence light Y.

The wavelength conversion layer 32 receives the excitation light B emitted from the excitation light source 110 and intersects the optical axis of the excitation light B, a light incident surface 32a, a light emission surface 32b facing the light incident surface 32a, and light incidence. It has a connecting surface 32c that connects the surface 32a and the light emitting surface 32b. The light incident surface 32a is located closer to the translucent member 33 than the first surface 31a of the support member 31, and the light exit surface 32b is
It is located in the hole 31h with respect to the second surface 31b of the support member 31. The connection surface 32c is provided in contact with the reflection film 35 provided on the inner peripheral surface of the hole 31h of the support member 31. The light emitting surface 32b may be formed on the same plane as the second surface 31b of the support member 31. The wavelength conversion layer 32 is a transmission type wavelength conversion layer having a light incident surface 32a and a light emitting surface 32b separately.

As the phosphor particles, for example, YAG (yttrium-aluminum-garnet)-based phosphor is used. In addition, the forming material of the phosphor particles may be one kind, or a mixture of particles formed by using two or more kinds of materials may be used. In the wavelength conversion layer 32,
It is preferable to use one having excellent heat resistance and surface workability. Such a wavelength conversion layer 3
As 2, a phosphor layer in which phosphor particles are dispersed in an inorganic binder such as alumina, a phosphor layer in which phosphor particles are sintered without using a binder, or the like is preferably used.

The dichroic film 34A is provided on the light incident surface 32a of the wavelength conversion layer 32. The dichroic film 34A has a characteristic of transmitting the blue excitation light B emitted from the excitation light source 110 and reflecting the yellow fluorescent light Y generated by the wavelength conversion layer 32.

The translucent member 33 is provided so as to face the light incident surface 32 a of the wavelength conversion layer 32, and the bonding member 3
It is fixed to the first surface 31 a side of the support member 31 via 6. The translucent member 33 of the present embodiment is made of sapphire having high thermal conductivity, and is composed of a plano-convex lens having a hemispherical shape in cross section. The translucent member 33 has a flat surface 33f and a convex surface (curved surface) 33d. The flat surface 33f of the translucent member 33 faces the light incident surface 32a of the wavelength conversion layer 32 with the dichroic film 34A in between. The convex surface 33d of the translucent member 33 is a curved surface protruding in the direction opposite to the traveling direction of the excitation light B from the excitation light source 110.

The antireflection film 34C is provided on the flat surface 33f of the translucent member 33. The antireflection film 34C has a property of suppressing the reflection of the excitation light B, and when formed on the flat surface 33f of the translucent member 33, the transmission efficiency of the excitation light is improved. The antireflection film 34C may not be provided on the entire flat surface 33f. For example, the antireflection film 34C may be provided at least in a portion of the flat surface 33f facing the light incident surface 32a (dichroic film 34A).

The bonding member 36 includes an antireflection film 34C provided on the flat surface 33f of the translucent member 33,
The transparent member 33 is arranged between the first surface 31 a of the support member 31 and the first surface 31 a, and the translucent member 33 is joined to the support member 31. As the joining member 36, those having high thermal conductivity are preferable regardless of translucency and non-translucency. For example, solder, a heat conductive sheet, etc. are mentioned. The joining member 36 needs to have a certain thickness to secure the joining strength. Therefore, in the present embodiment, the thickness along the optical axis direction is set to be thicker than several tens of μm, and is preferably thicker than the air layer 37 described later.

An air layer 37 is provided between the translucent member 33 and the wavelength conversion layer 32. That is, the flat surface 33f of the translucent member 33 (the antireflection film 34C on the flat surface 33f) and the wavelength conversion layer 3
An air layer 37 is provided between the second light incident surface 32a (the dichroic film 34A on the light incident surface 32a). In the present embodiment, the light incident surface 32a of the wavelength conversion layer 32 projects in a direction opposite to the traveling direction of the excitation light from the excitation light source 110 so that the air layer 37 is thinner than the bonding member 36. ing. That is, in the present embodiment, the light incident surface 32a of the wavelength conversion layer 32 is arranged so as to project toward the light transmissive member 33 side with respect to the first surface 31a of the support member 31. Therefore, a step portion 38 is formed between the first surface 31 a of the support member 31 joined to the translucent member 33 and the light incident surface 32 a of the wavelength conversion layer 32. In this embodiment,
From the viewpoint of heat transfer, the thickness of the air layer 37 along the optical axis direction is preferably 20 μm or less, and 10
More preferably, it is less than or equal to μm.

Fine irregularities are formed on the flat surface 33f of the translucent member 33 (the antireflection film 34C on the flat surface 33f) or the light incident surface 32a of the wavelength conversion layer 32 (the dichroic film 34A on the light incident surface 32a). It may have been done. Even if fine irregularities are formed on the flat surface 33f or the light incident surface 32a, when the transparent member 33 and the wavelength conversion layer 32 are brought close to each other, the flat surface 33f and the light incident surface 32a are separated from each other. Even if they partially come into contact with each other, the dichroic film 34A on the wavelength conversion layer 32 side and the antireflection film 34C on the translucent member 33 side do not come into close contact with each other and the air layer 37 is not formed. The air layer 37 is formed between the light incident surface 32a of the wavelength conversion layer 32 and the flat surface 33f of the translucent member 33, or between the dichroic film 34A and the antireflection film 34C.

Therefore, as shown in FIG. 3, the air layer 37 may be provided with a constant thickness between the dichroic film 34A and the antireflection film 34C in a completely separated state without contacting each other. The dichroic film 34A and the antireflection film 34C, or the wavelength conversion layer 32.
An air layer 37 having a non-uniform thickness may be formed in a state where the light incident surface 32a and the flat surface 33f of the translucent member 33 are partially in contact with each other.

As shown in FIG. 4, the space in which the air layer 37 is provided communicates with the external space of the wavelength conversion element 30 via the two vent holes 36t and 36t provided in the joining member 36. The light incident surface 32a of the wavelength conversion layer 32 rises to about 150° C. due to heat generation. Wavelength conversion layer 32
When the air layer 37 expands due to the heat generation of the air, the air flows through the vent holes 36t and 36t and is discharged to the external space of the wavelength conversion element 30, and the support member 31 and the translucent member 33 are separated from each other. Can be prevented.

The vent hole 36t is formed of a region between the translucent member 33 and the support member 31 where the joining member 36 does not exist. It suffices that there be at least one vent hole 36t, and the number, position, size, etc. of the vent holes 36t are not limited to the illustrated configuration, and are appropriately set according to the volume of the air layer 37 and the like.

The air layer 37 is translucent, and it is not necessary to consider heat resistance while suppressing interface reflection.
On the other hand, the translucent member 33 is joined to the supporting member 31 supporting the wavelength conversion layer 32 by the joining member 3
It is well joined via 6.

Also, the thinner the air layer 37, the higher the heat transferability. For this reason, in this embodiment, the thickness of the air layer 37 is smaller than the thickness of the joining member 36. That is, the light incident surface 32a of the wavelength conversion layer 32 is projected toward the transparent member 33 side with respect to the first surface 31a of the support member 31, and the wavelength conversion layer 32 is arranged as close as possible to the transparent member 33. did. This facilitates the heat of the wavelength conversion layer 32 to be transmitted not only to the support member 31 side but also to the translucent member 33 via the air layer 37. The cooling means 13 including the support member 31 and the translucent member 33 can improve the heat dissipation of the wavelength conversion layer 32 and prevent the wavelength conversion efficiency of the wavelength conversion element 30 from decreasing.

Particularly, when the wavelength conversion layer 32 is not rotated like the wavelength conversion element 30, that is, when the wavelength conversion element 30 is not a phosphor wheel, the temperature rise of the wavelength conversion layer 32 becomes a problem.
In the present embodiment, since the translucent member 33 is arranged on the light incident surface 32a side of the wavelength conversion layer 32 and the air layer 37 is provided between the translucent member 33 and the wavelength conversion layer 32, the wavelength conversion is performed. Layer 32
The heat is easily transmitted not only to the support member 31 side but also to the translucent member 33 through the air layer 37. The cooling means 13 including the support member 31 and the translucent member 33 can improve the heat dissipation of the wavelength conversion layer 32 and prevent the wavelength conversion efficiency of the wavelength conversion element 30 from decreasing.

Furthermore, since the translucent member 33 is formed of sapphire having high thermal conductivity,
The heat generated in the wavelength conversion layer 32 can be effectively dissipated in the translucent member 33.

In addition, in the present embodiment, the bonding member 3 that bonds the wavelength conversion layer 32 and the translucent member 33.
The air layer 37 and the external space of the wavelength conversion element 30 are communicated with each other through the vent hole 36t provided in the nozzle 6, so that the air flows. Thereby, the air (air layer 37) expanded by the heat generation of the wavelength conversion layer 32 can be discharged to the outside through the vent 36t. Thereby, damage to the wavelength conversion element 30 due to expansion of the air layer 37 can be suppressed.

As described above, according to the configuration of the present embodiment, since the wavelength conversion element 30 having high heat dissipation is provided, the light source device 2A having high wavelength conversion efficiency is realized and the projector 1 having high reliability is obtained. ..

[Second Embodiment]
Next, a light source device according to the second embodiment of the present invention will be described.
The light source device of the present embodiment described below differs from the configuration of the first embodiment in that it includes a blue separation type light source device 2B. Therefore, in the following description, the configuration of the light source device 2B will be described in detail, and description of common points will be omitted. In addition, in each drawing used for the explanation, FIG.
The same components as those in FIG. 5 are designated by the same reference numerals.

FIG. 6 is a diagram showing the configuration of the light source device according to the second embodiment.
As shown in FIG. 6, the light source device 2B includes an excitation light source 110, a collimating optical system 42, a retardation plate 43, a polarization separation element 44, a first homogenizer optical system 45, and a first condensing optical system. 46, a wavelength conversion element 70, a first pickup lens 48, a dichroic mirror 49, a total reflection mirror 50, a second retardation plate 51, a second homogenizer optical system 52,
A second condensing optical system 53, a reflective rotary diffusing element 54, a second pickup lens 55,
Is equipped with.

Of the light source device 2B, the excitation light source 110, the collimating optical system 42, the phase difference plate 43, the polarization separation element 44, the first homogenizer optical system 45, the first condensing optical system 46, and the wavelength conversion element 70.
The first pickup lens 48 and the dichroic mirror 49 are sequentially arranged on the optical axis 100ax.

The retardation plate 43 is composed of a half-wave plate having a rotation mechanism. The phase plate 43 is
Of the excitation light B condensed by the collimating optical system 42, P-polarized light and S-polarized light are converted into arbitrary ratios. The retardation plate 43 may be a quarter-wave plate, and the polarization state (
There is no particular limitation as long as the ratio of P-polarized light and S-polarized light can be changed.

The polarization separation element 44 is a so-called plate-type polarization beam splitter (PBS) and has an inclined surface forming an angle of 45° with the optical axis 100ax. The polarization separation element 44 allows the P-polarized component of the incident light to pass through and reflects the S-polarized component. The P-polarized component passes through the polarization separation element 44 and advances toward the first homogenizer optical system 45. The S-polarized component is
The light is reflected by the polarization separation element 44 and proceeds toward the total reflection mirror 50.

The first homogenizer optical system 45 includes, for example, a first multi-lens array 45a,
And a second multi-lens array 45b. The first homogenizer optical system 45 makes the light intensity distribution of the excitation light uniform on the wavelength conversion layer described later, that is, a so-called top hat distribution. The first homogenizer optical system 45 superimposes a plurality of small light fluxes emitted from the plurality of lenses of the first multi-lens array 45a on the wavelength conversion layer together with the first condensing optical system 46. As a result, the light intensity distribution of the excitation light B with which the wavelength conversion layer is irradiated is made uniform.

The first condensing optical system 46 is arranged in the optical path from the first homogenizer optical system 45 to the wavelength conversion element 70, condenses the excitation light B and makes it enter the wavelength conversion layer of the wavelength conversion element 70.
In this embodiment, the first condensing optical system 46 is composed of a convex lens.

The first pickup lens 48 is, for example, a convex lens, and substantially collimates the yellow light Y emitted from the wavelength conversion element 70.

The dichroic mirror 49 allows the yellow light Y emitted from the wavelength conversion element 70 to pass therethrough, and reflects the blue light B incident from a direction orthogonal to the yellow light Y in the same optical axis direction as the yellow light Y. It is a mirror.

The total reflection mirror 50 is arranged in the optical path of the blue light B, and totally reflects the blue light separated by the polarization separation element 44 toward the second retardation plate 51.

The second retardation plate 51 is a quarter-wave plate (λ/4 plate). The second retardation plate 51 converts the S-polarized blue light emitted from the polarization separation element 44 into circularly polarized light.

The second homogenizer optical system 52 includes, for example, a first multi-lens array 52a,
And a second multi-lens array 52b. The second homogenizer optical system 52 superimposes a plurality of small luminous fluxes emitted from the plurality of lenses of the first multi-lens array 52a, together with the second condensing optical system 53, on the reflective rotary diffusing element 54. As a result, the light intensity distribution of the blue light B with which the reflective rotary diffusing element 54 is irradiated is made uniform.

The second condensing optical system 53 includes a reflective rotary diffusing element 54 from the second homogenizer optical system 52.
The blue light B, which is arranged in the optical path up to and is converted into circularly polarized light, is condensed and made incident on the reflection type rotary diffusion element 54. In the present embodiment, the second condensing optical system 53 is composed of a convex lens.

The reflective rotary diffusing element 54 diffuses and reflects the light beam emitted from the second condensing optical system 53 toward the second pickup lens 55. Among them, as the reflection type rotary diffusion element 54, it is preferable to use one that diffuses and reflects the light beam incident on the reflection type rotation diffusion element 54 with Lambertian reflection or a characteristic close to Lambertian reflection.

The second pickup lens 55 is composed of, for example, a convex lens, and includes the reflective rotary diffusing element 54.
The blue light B emitted from is made substantially parallel. The collimated blue light B travels to the dichroic mirror 49, and is reflected by the dichroic mirror 49 in the same direction as the yellow light Y traveling in a direction orthogonal to the blue light B.

In this way, the light beam (blue light B) emitted from the reflective rotary diffusion element 54 is combined with the fluorescent light (yellow light Y) that has passed through the dichroic mirror 49, and white illumination light WL is obtained. The white illumination light WL enters the color separation optical system 3 shown in FIG.

(Wavelength conversion element)
Next, the configuration of the wavelength conversion element according to the second embodiment will be described.
FIG. 7 is a sectional view of the wavelength conversion element according to the second embodiment taken along a plane including the illumination optical axis 100ax of FIG.
As shown in FIG. 7, the wavelength conversion element 70 includes a support member 71 having a hole 71h (non-bonding portion).
And the cooling means 73 having the translucent member 33, the reflection film 35, the wavelength conversion layer 72, the dichroic film 34A, the dichroic film 34B, and the antireflection film 34C. An air layer 37 is provided between the elastic member 33 and the elastic member 33.

The wavelength conversion layer 72 of the present embodiment is excited by the blue excitation light B emitted from the excitation light source 110 and emits the yellow fluorescent light Y. The thickness of the wavelength conversion layer 72 is set to a thickness capable of converting all of the incident excitation light B into yellow light Y.

The light incident surface 72a of the wavelength conversion layer 72 is provided with a dichroic film 34A that transmits the blue light B and reflects the yellow light Y. The light emitting surface 72b of the wavelength conversion layer 72 is provided with a dichroic film 34B that reflects blue light and transmits yellow light.

Also in the present embodiment, the wavelength conversion layer 72 has the light incident surface 72 a of the first supporting member 71.
Of the bonding member 36 that joins the transparent member 33 and the support member 71 to each other. Is also thin.

As described above, also in the configuration of the present embodiment, it is possible to obtain the wavelength conversion element 70 that suppresses interface reflection, has high heat dissipation, and suppresses a decrease in wavelength conversion efficiency, and requires less input power. It is possible to provide the projector 1 having a bright projection surface.

The preferred embodiment of the present invention has been described above with reference to the accompanying drawings, but the present invention is not limited to the example. It is obvious to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims, and of course, the technical scope of the present invention is also applicable to them. Understood to belong to.

DESCRIPTION OF SYMBOLS 1... Projector, 2A, 2B... Light source device, 4B, 4G, 4R... Light modulation device, 6... Projection optical system, 13, 73... Cooling means, 30, 70... Wavelength conversion element, 31, 71... Support member,
31a... 1st surface (bonding surface), 31h, 71h... Hole (non-bonding part), 32, 72... Wavelength conversion layer, 32a, 72a... Light incident surface, 32b, 72b... Light emitting surface, 32c... Connection surface , 33... Translucent member, 33d... Convex surface (curved surface), 36... Joining member, 37... Air layer, 38... Step portion, 110
…Excitation light source, B…Excitation light

Claims (7)

A wavelength conversion layer having a light incident surface on which excitation light is incident, a light emitting surface facing the light incident surface, and a connection surface connecting an end of the light incident surface and an end of the light emitting surface. When,
A supporting member that supports the wavelength conversion layer and is provided in contact with the connection surface, and a curved surface that protrudes in a direction opposite to the traveling direction of the excitation light, and faces the light incident surface of the wavelength conversion layer. And a cooling member having a light-transmitting member that is joined to the supporting member via a joining member,
An air layer is provided between the light incident surface of the wavelength conversion layer and the translucent member,
The wavelength conversion element, wherein the air layer is thinner than the thickness of the joining member. The supporting member has a non-bonding portion that is opposed to the translucent member and is not bonded to the translucent member, and the wavelength conversion layer is disposed in the non-bonding portion.
The wavelength conversion element according to claim 1. The support member has a joint surface joined to the translucent member,
The light incident surface of the wavelength conversion layer projects in a direction opposite to the traveling direction of the excitation light with respect to the joining surface, thereby forming a stepped portion between the joining surface and the light incident surface. ,
The wavelength conversion element according to claim 1 or 2. While the translucent member includes sapphire, the curved surface has a hemispherical shape,
The wavelength conversion element according to any one of claims 1 to 3. The joint member is provided with a vent for communicating the air layer and the external space.
The wavelength conversion element according to any one of claims 1 to 4. An excitation light source that emits the excitation light,
The wavelength conversion element according to claim 1, wherein the excitation light is incident on the light source device. A light source device according to claim 6;
An optical modulator for generating image light by modulating the light emitted from the light source device according to image information;
A projection optical system that projects the image light.

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